<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        p {
            color: rebeccapurple;
        }

        a {
            /*去掉下划线*/
            text-decoration: none;
        }

        ul {
            /*去掉小圆点*/
            list-style: none;
        }

        #title {
            color: red;
        }

        .cla {
            color:black;
        }
    </style>
</head>

<body>
    <p>
        <a href="https://www.baidu.com/">百度</a>
    </p>
    <ul>
        <li>课程1</li>
        <li>课程1</li>
        <li>课程1</li>
    </ul>
    <p id="title">hello</p>
    <p class="cla">hello</p>
    <p>hello</p>
    <p>hello</p>
</body>

</html>